Grinding mill including vibrating feed hammer



GRINDING MILL INCLUDING VIBRATING FEED HAMMER Filed Aug. 4, 1955 April 1, 1958 M. G. ELLSWORTH 3 Sheets-Sheet l I I INVENTOR 57 jV erZe CZ Filszz/orf/a 3 Sheets-Sheet 2 INVENTOR.

BY XM W -E i: a

Merle GZZZszz/orifi April 1, 1958 M. G. ELLSWORTH GRINDING MILL INCLUDING VIBRATING FEED HAMMER Filed Aug. 4, 1955 A ril 1, 1958 M. G. ELLSWORTH 2,828,924

GRINDING MILL INCLUDING VIBRATING FEED HAMMER Filed Aug. 4, 1955 s Sheets-Sheetfi II G I gy INVENTOR;

- n d States Patent GRINDING MILL INCLUDING VIBRATING FEED HAMMER Merle Gordon Ellsworth, Bloomington, Ill.

Application August 4, 1955, Serial-No; 526,496-

4 Claims. (Cl. 241-222) This-invention relates generally to grinding millsand has to do more particularly with a novel mill for grinding;

granular materials, such as sand and gravel.

An object of the present invention is toprovide a-new and improved grinding mill.

Another object is to provide a--new and improved grinding mill of relatively simple construction capable 2,828,924 Patented Apr. 1,4958

view taken along ever,-it is to be understood that the machine is not limited to thisuseandmay be-used for grinding anyone of a number of materials of a granular nature to a greater degree of fineness. The machine isespecially well adapted for grinding gravel to produce'fine-sand and by way of example, it may be used, for example, to grind gravel of a sizeof As" toproduce 50 mesh and 100 meshsand,

It should also-be understood that by reason of'the adjustability. of the spacing of the rolls themachine may be set'to produce either a very fine sand or a somewhat coarser sand; depending upon the adjustment of the rolls. Owing to the grinding or crushing action of the rolls" and also-particularly tothe crushing action afforded by the hammer (ashereinafter described), the material which passes through therolls is not necessarily uniform in size but-may range fromthe largestsize particles which can pass between the rolls to very fine particles. Accordingly the product whichisproduced by the machine will consist of particles of various sizesn This product may and ordinarily .-will be screened in order to provide'sand; of difrolls thematerial to be .ground and for forcibly feeding such material into the nip of the rolls.

Another object is to. providea grinding mill of the type having a pair of closely spaced, opposed rolls, wherein is provided ashammer positioned above the nip of rthe rolls and vibrated relatively to the rolls to crush the material against the rolls and thereby reduce the size of theparticles' to that whichwill be nipped by the rolls and to aid in feeding the material to the nip of the rolls; 7

Still another object is to provide a grinding mill having a pair of opposed, closely spaced grinding rolls wherei in is provided novel mounting meansfor the rolls which is simple and inexpensive and whereby the spacing- 0f the rolls may be quickly and easily effected.

Another object is to provide a simple, inexpensive but eifective means for mounting the grinding rolls of a grinding mill whereby the rolls maybe quickly and-easily removed and replaced.

Another object is to provide a grinding mill-having a simple and effective mechanism for preliminarily crush ing particles of the material to be ground prior'to itspassage between therolls.

Another object is to provide a grinding millhaving a new and improved feed means for forcibly feeding to the nip of the rolls the material to be ground.

Other objects are to provide a: grinding mill for grinding relatively hard granular material such. as sand and gravel, which mill is simple in construction, relatively inexpensive to construct, eifectivein operation, capable of use over a long period Without requiring repair or replacement of parts, and which requires a minimum of attention and care during operation. I

Other objects and advantages of the invention will appear fromthe following description taken in connection with the appended drawings-wherein:

Figure l is a side'elevational view of a machineconstructed in accordance with my invention;

ferent mesh for use in different applications. However, the construction of the machine is such that a relatively a fine sand is-produced even without screening.

For convenience in describing my invention I have designated herein that portion of the plane passing through the axes of the two rolls which lies-between the opposing surfaces of the rolls as the tangentzonez It 'will'be understood of course that the rolls are not in actual contact but since they are relatively closely spaced it is believed that the zone of closestapproach of the rolls plane tangent to the uppermost surfaces of the-roll.

t Fig. 2 is a fragmentary view of the vibrating mechanism of'zthe'zmachine:.of'Fig. 1 and'illustrating somewhat dialgramrnaticallyithe action of such mechanism; -Fig. 3 is a top plan view ofithesmachine 0f ;Fig'. 1

Fig. 4 is a fragmentary, sectional view taken along construction and is formed by a cylindrical nienib'erZi.

The mill of my invention includes a casing 10 formed 'by a pair of spaced side walls 11' each having out-turned flanges 12 at their upper portions and spaced end'walls 13 connecting the side walls at their end portions; The casing 10 is supported by any suitable IneansQnot shown).

The top of the casing 10 is open 'to permit feeding of sand or gravel to the rolls (hereinafter described) "and is open at the bottom to permit discharge of the ground material. If desired, the lower portionof the casing may be formed to provide a discharge hopper as shown" particularly in Fig. l of the drawings, although this-is not necessary.

Preferably I provide means for carrying away the ground material to a point of screening, storage or other disposition and for this purpose I provide a travelling conveyor 15 disposed below'the bottom of the casing '16. However, the mill may discharge onto-screening' means or onto a storage area, or into a storage bin.

Mounted within the casing 10 is a pair of grinding rolls 20 which are positioned in opposition to rotate about parallelaxes lying-in a horizontal plane. The rolls 24) are so mounted that the distance between their surfaces at" their point of closest approach is equal to the maximum-size of the grains or particles of the material to 'be' produced by grinding. Each of the rolls 20 preferably is ofhollow and a pair of end members 22 rigidly secured-in and supporting the cylindrical member 21, as" byweldingli The roll 20 and particularly the cylindrical portion 21 t1 ere.

the rolls preferably are smooth 'in a sand mill or other similar mill.

of is formed from a hard, long-wearing and shock-resistant material and for this purpose I prefer to use a suitable manganese steel although other suitable materials may be employed. The peripheral, grinding surfaces of in order to insure fineness of the ground product.

The rolls 20 are of the same diameter and are so supported that they rotate about axes which are parallel and in the same horizontal plane. Each of the rolls 20 is secured on a mounting shaft 25 in a removable manner as by keys26 cooperating with slotsinthe end members 22 and in the shaft25. Each shaft 25 extends at both ends through openings 30 in the side walls 11 and is journaled in bearings 31. form and is mounted in a rectangular recess 32 in the outer face of the side wall 11 and in alignment with the corresponding opening 30. The bearing recess 32 is of Each bearing31 is of rectangular 5 such height as to snugly fit the bearing 31, but with sufiiv cient clearance to permit sliding adjustment of the bearing 31 therein in a horizontal direction. On the other hand the bearing recess 32 is of slightly greater length than the bearing 31 sothat the bearing may be adjusted horizontally in the opening. A shim 33 is provided I which is inserted between the bearing and the corresponding end of the recess 32.

The. foregoing arrangement permits the adjustment of the rolls in a direction toward and away from each other in order to accommodatefor wear in the surfaces of the roll. When the rolls are new and are of full peripheral dimensions the shims 33 are disposed at the end of each 7 recess 32 nearest to the other recess so that the axes of the rollsare at the greatest separation. As the surfaces of the rolls wear and the clearance between the points the frame to a position closest to the first roll. Thus two different adjustments are provided.

Preferably I provide one shim for each of the bearings as I have found that for most purposes this is sufficient. However, it will be understood that a plurality of thinner shims may be provided in each bearing recess thereby to provide afiner adjustment-ofthe bearings in their recesses. Thus, where'a plurality of such shims are provided the adjustment of each roll may be made in steps successivelyasthe surfaces ofthe rolls are worn rather than in a single operation as where. but a single shim is employed in each bearing recess.

The bearings at one side of the casing (right-hand side as viewed in Fig. 4) are retained in their respective recesses 32 by cover plates 35 suitably secured to the side member 11 as by screws 36. It should be explained at. this point that the arrangementof the key and slot connections between the shaft 25 and rolls 20, and the removable bearing arrangement permits the rolls to be removed readily from the machine and replaced when this is desired, as when the surfaces become so worn that they are incapable of grinding the material to' the desired degree of fineness. t

While I have shown and described the preferred form of mounting arrangement for the rolls in order to provide the desired adjustment, it will be'understood that.

other adjustable bearing means may be provided. The

construction which I have shown and described is extremely. simple and effective in'operation and is not readily subject to mal-functioning from any cause and particularly the presence of sand and dust as Means are provided for rotating the rolls in" synchronism and at the same surface speeds. To this end I provide driving means which preferably isan electric motor 40 suitably supported, as by a bracket 41 fixed to the casing 10. Fixed on the motor shaft is a driving gear 42 which meshes with a driven gear 43 secured as by a key 44 on the shaft 25 carrying the roll 20. A similar gear 46 is similarly secured to the other shaft 25 and meshes with the first gear 43 whereby it is driven by the latter. Thus it will be seen that upon energization of the motor 40 both of the gears 43 and 46 are rotated and the rolls correspondingly rotated. The gearing arrangement is such and the direction of rotation of the motor is such that the rolls are-rotated in opposite directions with their peripheries moving downwardly at their opposed inner portions (as indicated by arrows in Fig. 5 of the drawings).

I provide means for crushing against the peripheries of the rolls prior to its passage through the rolls the material, such as gravel for example, being delivered to the approach'zone. Suchmeans also is so constructed as to force the material into the nip of the rolls. To this end I provide a hammer 50 which is suitably supported (by means hereinafter described) pivotally in a position between the rolls and above the tangent zone. The hammer is formed with a head 51 formed with striking faces 52 which are planar and which converge to a bottom edge. While the angle between the faces 52 may be varied somewhat I prefer to form the faces 52 so that they are at similar angles to a longitudinal medial plane through the hammer 50 and which planes are at an angle of approximately degrees.

The size and proportions of the hammer and particularly the head 51 thereof may be varied somewhat but I prefer to provide a head generally similar in size and arrangement to-that shown in Fig. 5. Accordingly I prefer to form and locate the head 51 so that when it i is in its lowermost position the lower edge thereof is located above the tangent zone. I prefer to form the faces 52 of such length that they extend a distance of approximately one-third the distance from the tangent zone to a plane'tangent to the top surfaces of the rolls.

' The hammer 50 preferably is of such width that it extends throughout the lengths of the rolls 20.

The hammer;50 is formed of suitable material, such as metal which provides adequate weight and strength i and I preferto form it on material which is resistant to wear and abrasion and shock and which therefore does not require frequent replacement. To this end I form the hammer'of-mangancse steel similar to the material from which the rollsare formed, although other suitable materials may be used.

While I have shown the hammer 50 as comprising an enlarged end-portion and a reduced shank, it will be understood that the portionabove the head may take other forms. However, the, arrangement shown is preferred as such arrangement is deemed to be most effective for the purposes for which it is employed. For convenience in describing the invention I employ the term head{ to designate that portion of the hammer having the striking faces, that is, the faces adapted to crush the material between'the hammer and the rolls.

The hammer 50 is. supported for swinging movement between the rolls and for vertical reciprocation by a mechanism now to be described. The hammer 50 is formed with a bearing portion 53 at its upper end which is supported on a shaft54 for pivotal movement on the shaft whereby the hammer is suspended pivotally by the shaft 54. The shaft 54 is secured in and carried by a vertical reciprocating movement by a pair of guide brackis inevitable a way in which the corresponding end 'of'the hangerbar 55 'slides and isrguided. p

The hanger bars 55 and the members carried thereby are supported normally in. a predetermined position by I a pair of coil springs 60 interposed between the bottom of each hanger bar 55 and the top of the flange ,11 whereby the hanger bars and connected elements are resiliently supported. The springs 60 thus serve to cushion the hanger bars 55 and connected members as the latter.

' tioned openings 63 in the hanger bars 55. Interposed between the heads of the bolts 61 and the top of thehanger bars are buffer springs 65 and washers 66,.which buffer springs cushion the upward movement of the hanger bars 20 55 and connected elements and prevent the hanger bars from striking the heads of the bolts 61.

A shaft 70 is journaled in bearings 71 secured asby bolts 72 to the upper surfaces of the two hanger bars 55 respectively. Secured on they shaft 70 for rotation' thereby are a pair of vibrator wheels'76 each of unbalanced construction and thereby adapted to cause vertical reciprocation or vibration of the hanger bars 55 when the wheels are rotated. The wheels 76 are so formed as .to be unbalanced by weighting one portion of the periphery of each to a greater extent than the remaining portions. Preferably I accomplish this by forming the wheels of generally dished construction with a flange which has a weighting portion 77 extending inwardly therefrom toward rapid to providesuch crushing action ata suflicientrate to operate the machine at the optimum capacity.

V It isdesirable to insure that the surfaces of the rolls are clean and do not have wet sand adhering thereto as they move toward the nip. Accordingly I prefer to provide a pair of scrapers 96 which are disposed in position to bear against the peripheries of the rolls at positions somewhat below and outwardly of the nip and preferably above the lowest points on the roll peripheries. However the exact location of the scrapers 90 is not critical, it beingdesirable merely that they remove the wet sand or other adherent material prior to the time the rolls approach the point at which material to be ground is delivered thereto. The scrapers 90 are supported in any suitable manner and preferably are secured at their .-ends to the sides 11 of the flange.

It will'be understood that the gravel to be ground may be deposited onto the rolls in any suitable manner. I-Iowever I prefer to provide a hopper 100 for guiding the material onto the rolls and into the approach zone between the rolls. The hopper 166) may take any suitable form and preferably includes side plates 101 and end plates 102, the hopper being suitably secured to the frame 10 in a suitable manner (not shown) so as to support it above the rolls. Means (not shown) maybe provided for preventing gravel from falling onto the shaft 70 and V the shaft '54 which means'may take the form of a cover the center of the wheel to a greatercxtent than the re I movement of the shaft 70. Accordingly, the motor .83

preferably is mounted for slight vibration in order to allow for the vibration of the shaft 70, although in certain cases this is not necessary as the drive belt 81 will accommodate such vibratory movement. Therefore, I support the motor 83 on a plurality of springs 84 which are seated on a bracket 85 secured to a casing 10 and con- =nected to the bracket 85 as by bolts 86.

The suspension .bars and the members carried thereby are not restricted against vertical movement except as such movement is restrained somewhat by the springs,

but are onlyprevented from moving laterally, and hence the rotation of the vibrator wheels causes the suspension bars and connected members to be vibrated vigorously as the vibrator'wheels are rotated.

It will be seen that the shaft 54 from which the hammer 50 is suspended and the shaft 70 which carries-the vibrator wheels are supported in such manner that they ously and in unison.

The vibrating mechanism is driven from a separate source of power from that driving the grinding rolls, principally .becauseit is preferable that the source of power for the vibrating mechanism permit the vibrating movement of the drive shaft 76 and the connected vibrating members. It is not necessary that the'drive of the vibrating mechanism be synchronized with the drive of the roils. In fact the rate of vibration of the hammer is not critical it being necessary only that the hammer be vibrated at a sufficient rate to provide the necessary momentum of the hammer to crush the particles of ma Efil'ial. It is preferable that the vibration be sufficiently or gable roof (not shown) extending between the side plates 101 of the feed hopper and disposed over such shafts. v

In the operation of my machine the motor 40 is suitably energized to rotate the rolls Zth At the sametime the motor 83 is energized to rotate the shaft 7t) carrying the vibrator wheels'76. As the latter are rotated they cause'vibration of the shaft 7t} on which they-are carried by reason of the'fact that they are eccentrically weighted andinherently tend to move the shaft 70 out of its normal position. Owing to the fact that the shaft '70 is constrained against movement, except vertical movement, the unbalanced condition of the wheels 76aitects only vertical vibration of the shaft 70. .The shaft '70 being can ri ed by the hanger bars 55 which are resiliently supported by the springs 69,. the vertical vibratory movement of the shaft 70 is permitted and enhanced, with the result that the hangers 55, together with the connected members, are vibrated in a vertical direction. The springs alsoflserve to contribute to this vibratory action.

'The vibratory movement of the hammer 50 causes it 'to.vibrate vertically with respect to the. surfaces of the rolls 26 facing the surfaces 52 of'the hammer 50. Thus any gravel particles which fall into the space between the faces 52 and opposing peripheries of the rolls 2d are crushed between a face of the hammer 50 and the opposing roll 2d. Since the hammer 5% is pivotally suspended it is vibrated laterally as well as vertically asa resultof striking against the faces of the rolls 20 or against parholes of gravel between. the faces 52 and the'rolls 29. This compound vertical and horizontal reciprocation results in a beating or hammering action whereby the hammer 59 crushes between its faces 52 and the opposed faces of the rolls '20 the larger sized particles of gravel. The smaller particles of gravel and the fragments of the larger particles which have been crushed and broken by the action of the hammer 59 fall into the nip of the rolls below the hammer 50 and are carried between the rolls. The larger of suchv particles are crushed between the rolls owing to the pressure of the rolls and the fragments of such particles together with the smaller particles pass between the rolls. The hammer 5d serves not only to hammer and crush between its surfaces and the opposing surfaces of the rolls the gravel which is in position to'be so 1 crushed but also serves to tamp and force feed into the 7 Thus it will be seen that, the vibrating action of the hammer 50"serves both-to crush the larger particles of gravel to a size such that they will be accepted by the nip of the rolls but also it serves to force feedthe material to the nip of the rolls so that should such material be of The material which passes between the rolls falls down onto the conveyor 50 and is carried to a point of storage or use or further processing. Thus, such material may be discharged to a storage pile, or a storage bin or passed toscreens to segregate different sizes of the sand orit may be carried to a point of use or; shipment, as will be understood. p,

It will be seen from the foregoing that my invention provides a highlyetfective grinding mill'for grinding relatively hard granular material suchas gravel to produce much finer material such as sand. The machine is simple, compact and positive in operation. It is inexpensive to construct and capable of operation over a long period of use without requiring repair or replacementof the parts. However, should such replacement of parts become necessary, as for example replacement of the rolls, this can be effected very readily in view 1 of the simple novel mounting arrangement of the rolls and such replacement can be effected rapidly and with a minimum of shut-down time. p

The operation of the machine is such that relatively coarse gravel may be crushed to provide relatively fine sand by a single pass of the gravel through the machine. This is accomplished by the use of two cooperating smooth rolls and the crusher and feeder mechanism employed, namelythe hammer and its mounting and actuating mechanism. Previously it was found necessary to use a corrugated roll and a smooth roll to preliminarily crush the material and it was therefore not possible to crush a relatively coarse material to form a relatively fine product in a single operation. After such relatively coarse material was passedthrough a corrugated and smooth roll and a relatively coarse product produced, the product after screening resulted in a considerable quantity of relatively coarse material. In accordance with my invention it is possible to crush material, for example of of an inch, to produce material not larger than 50 mesh and of which a considerable proportion is 100 mesh or finer.

I claim: 1. A grinding mill comprising a pair of grinding rolls,

means mounting said rolls in opposed relation for rota tion about parallel axes in a horizontal plane, means for rotating said rolls, and means for crushing against said rolls, material to be ground, prior to its passage past and between said rolls, including a hammer having a downwardly tapered head formed with planar striking faces opposite said rolls respectively and extending substantially throughout the lengths of said rolls, means pivotally supporting said hammer with the head thereof between said rolls above the tangent zone thereof for free lateral swinging movement, said supporting means being mounted for resilient movement in a vertical direction only, and an eccentric flywheel rotatably mounted on said ,supporting means for vertically vibrating said supporting means and said hammer.

2. A grindingmill comprising a pair of grinding rolls,

means mounting said rolls .in opposed relation for rotation about .parallel axes ,in a horizontal plane, meansfor rotating said ,rolls, and means for crushing against said rolls material to be ground prior to its passage past and between said rolls including a hammer having a downwardly tapered head formed with striking faces lying in planes extending at an angle of not more than 45 Q to each other, means ,pivotally supporting said hammer with thehead thereof between said rolls above the tangent'zcne thereof for free lateral swinging movement, said supporting means being mounted for resilient movement in a vertical direction only, and an, eccentric flywheel rotatablymounted on said supporting means for vertically vibrating said supporting means and said hammer.

3. A grinding mill comprising a pair of grinding rolls, means mounting said rolls in opposed relation for rotation about parallel axes in a horizontal plane and means for rotating said rolls, and means for crushing against said rolls material to be ground, prior to its passage past and between said. rolls, including a hammer having a downwardly tapered head, a suspension bar, means resiliently supporting said bar, means pivotally suspending said hammer from said bar for free swinging movement of said head between said, rolls and above the tangent zone thereof, means guiding said bar for vertical movement only, and means for vibrating said suspension bar.

4. A grinding millcomprising a pair of grinding rolls, means mounting saidrolls in opposed relation for rotation about parallel axes in a horizontal plane, means for rotating said rolls, and means for crushing against said rolls material to be ground, prior to its passage past and betweenlsaid rolls, including a hammer having a downwardly tapered head, a suspension bar, means resilientlysupporting said bar, means pivotally suspending said hammerfrom said bar with said head between said rolls and above the tangent'zone, means guiding said bar for vertical movement and means for vibrating said suspension bar.

References Cited in the file of this patent UNITED STATES PATENTS 285,031 Hammond et al. Sept. 18, 1883 295,533 Frey Mar. 25, 1884 1,045,454 Sturtevant Nov. 26, 1912 2,144,911 Cohn Q. Jan. 24, 1939 2,340,456 Dinley Feb. 1, 1944 FOREIGN PATENTS 13,386 Denmark June 22, 1910 18,407 Great Britain June 3, 1909 (of 1908) 38,138 Austria July 26, 1909 43,095 Denmark Sept. 22 1,930 587,809 Germany Nov. 10, 1933 

